In the related art, when attempting to efficiently acquire information from a picture or the like that is being played back on a display device or the like, playback in fast motion or the like is performed. This is because by playing back in fast motion, it is possible to increase the amount of information that can be acquired in unit time. However, when viewing a picture played back in fast motion, users (viewers) often miss necessary information.
If information is missed, an operation of rewinding the playback position may be simply performed. However, there is a problem in that a rewind operation needs to be performed every time missing occurs, which is troublesome. In addition, such an operation can lower the efficiency of information acquisition all the more.
For this reason, it is also common to adjust the playback speed automatically in accordance with features of a picture, such as lowering the playback speed in scenes with lots of motion or raising the playback speed in scenes with few motion in a picture to be played back.
For example, Japanese Unexamined Patent Application Publication No. 10-243351 discloses detecting visual features in a picture including sound, and playing back the picture while automatically adjusting the playback speed in accordance with the visual features.
Incidentally, there are also users who want to perform playback while raising the picture playback speed even in scenes with lots of motion. That is, it can be said that the scene in which a user wants to lower or raise the picture playback speed differs depending on the condition in which each individual user is put, and the ability and preference of the user.
That is, it is considered that if the amount of information to be provided can be optimized in accordance with the condition in which a user is put, and the ability and preference of the user, the user can efficiently acquire necessary information from a playback picture. However, to optimize the amount of provision of information in accordance with the condition, ability, and preference of the user, first, it is necessary to measure the condition and ability of the user, and measurement of such data requires use of a large-scale device such as an electro-encephalograph, an electrocardiogram, or NIRS (Near-Infrared Spectroscopy). That is, since the cost mounts up, it is often difficult to realize an information presentation system.
Another conceivable technique for acquiring internal conditions such as the user's condition, ability, and preference without using such a device is to make the user report these pieces of information by himself/herself. However, making the user perform a complicated operation such as a key input increases the load imposed on the user, and it is expected that this will hinder efficient acquisition of information by the user all the more.
The present invention has been made in view of the above points, and its object is to adjust the amount of information provided to a user adaptively by means of a simple method.